1. Don't pull your DB offline to fill in global fields. I wouldn't rely on that functionality.In your auto open script set the global fields to the values you want. You can store the persistent values in a 1 record Prefs table if you like...or just set them in the script. That way everyone gets the correct values and you never have to take the database offline.
2. Yes...you don't need a launcher file. Just have them log in using the "Recently" used files menu item in FileMaker. If you need more than that...
- Will it be 80 users al together or simultanous?
- Will you give them access via each their FileMaker client or via IWP/CWP?
- Server OS and Server hardware?
- How are you handling backup?
- Network at your school - speed?
But 80 users should not be a problem with FileMaker. Depending on the quality and size of your solution you can have houndreds of users connected at once on FileMaker Server Advanced.
Please give some input to the questions and I am sure that you will get some good suggestions.